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Honda SL90 – Speedtractor Industries

Posted on July 18, 2013 by Scott in Scrambler. 19 comments

Written by Ian Lee.

Looking back, I was pretty lucky I reckon. I got to grow up around vintage motocross bikes, learning to ride on 70s era Yamaha bikes. Although only smaller capacity bikes, I loved the feeling of riding something that had been ridden offroad for over 20 years, and could still go hard. I didn’t think there was any way you could improve on that. Until I layed my eyes on Speedtractor’s SL90. Or should that be SL600? A big bore late model engine matched with 70s styling, it’s very much the ideal mix in relation to the power to styling ratio. And it’s oh so pretty.

Starting off with an idea put forward by a customer, to relive his childhood by having an SL90 to cruise around on, the crew at bike builders were interested. However, due to the customer having grown some since his childhood, a bigger power plant might be in order. In the words of Matt from Speedtractor: “We worked up a few concepts based around larger capacity 250’s and 400’s infused with the old SL’s easy going style and the client really got into our idea for a sort of gargantuan fun bike. Now with each party egging each other on, we decided to take it to the next level, knowing of an ex-enduro racer parting with his XR600”. And so it all started coming together.

Speedtractor is a fan of factory feel parts, but with their own special flavour. Using a mix of NOS and vintage parts, the amount of thought put into the componentry of the build shows in the finished product. The tank used in the build took some time to locate, but it was worth it so “the proportions and the radii matched the very geometric casting of the XR’s lump, plus the fact it was centre seamed and came from a Honda was icing on the cake”.

To keep with the SL styling, the frame was coated in silver urethane, then looped to suit the seat profile. Integrated into the seat are the rear indicators, the vibrations have a tendency to crack indicator mounts on the guards. Tire size at the front was dropped to 18 inch, to match the rear, trials tires continue the homage to the owner’s childhood SL90.

To ensure of power to match it’s aesthetics, the intake & exhaust system has been given a touchup. The factory air box was kept because it “comes in handy in sandy & muddy conditions” but fitted up with a free flowing air filter. This all helps the FCR carb to breathe, giving the bike ‘an insatiable appetite for rear tires”.

When purchased, the XR had a decent race pipe setup, but “the routing and position were way too perfect and space efficient’ for the required look. A set of new headers were fashioned up, ensuring no power was lost, rounding out in a slimline megaphone, with an adjustable baffle system. According to Speedtractor this makes for a “compact sexy version of a Supertrapp, with a delightfully gravelly snarl to it”.

The time and energy put into the breathing parts of the bike paid off, with the test pilot almost thrown off the back on the first shakedown run. When purchasing the bike, the previous owner had mentioned something about the engine being tinkered with, and this could have something to do with the “faster than expected” test run as well. After a dyno run, the estimate at the capacity of the engine leant more towards 700cc than what the bike left the factory with.

All in all, Speedtractor have taken their customers dream of having a grown up SL Honda and made it come true. High bars, 70s style brake lights, allow for nostalgia from childhood. On the other hand, the bored out engine and gravelly toned exhaust give you the pleasure being an adult and being able to afford a bike that throws back to your childhood, and is by all means awesome. And just so pretty.

  • nathas909

    I love it. More of this please, cool, nicely done, clean custom dirt bikes.

  • itsmefool

    Nice-looking, well-sorted dirt bike…wait a sec, these things shouldn’t be so clean! How ’bout sending it to my house so we can get it nice and dirty? Speedtractor FTW; great job, guys.

    Oh, and how about a sound file of this beaut being revved up? It’d be cool to hear that snarl!

  • revdub

    Perfection. The best of both worlds. My kudos the builders. This machine is beautiful and I bet it’s a whole lot of fun to ride.

  • Joe Freitas

    I love this bike! Anybody know what tank that is? How about the rear swingarm?

    • Randy Moran

      ’69 CB350 tank

  • Too sweet. Looks like a factory bike – or what a factory bike should look like. It’s got great stance, beautiful color choice, clean lines and looks like its meant to be ridden. I wouldn’t change a thing.

  • taka-tz

    This build has me grinning like a possum eating shit.

  • Roadracer Al

    That is just lovely — I’ve been shopping for a vintage bike, and looking for a SL350. I think I’d like living with this a lot more than a real vintage bike with real vintage power and real vintage brakes. Best of all possible worlds with this build.

  • Tony

    Great concept. It would be great if Honda decided to produce a retro SL like this (sort of like their retro CB1100F).

    • barney fife

      Their new CB1100 is nice but feel that Honda didn’t quite have the courage of their own convictions design wise. A lot of people seem to think they didn’t go far enough ‘retro wise’. The bike looks much better (IMHO) with the aftermarket early style tank etc. presently being offered by a Japanese aftermarket parts builder….very expensive though.

      • Tony

        I agree about the “not going far enough”, however, the CB1100F is a step in the right direction. I own the 1983 version and I’d like to add a 2013 to my stable…

  • Tony

    Here’s what the 1969 90cc version looked like:

  • Cliff Overton

    Oh so sweet – a real wolf in sheep’s clothing there.
    Beautifully built and perfect for the congested commute.

  • barney fife

    Beautiful looking. I’d buy a new one if Honda made them. 60’s 70’s designs with those organic lines are so much better looking than the design monstrosities they pedal now.

  • Davidabl2

    I hope Honda is well aware of this bike..It’s too bad they aren’t showing it as a concept bike at all the shows. And aren’t into doing any small-run production motorcycles.

  • Britbike

    As always, Pipeburn posts the best bikes out there. A real testament to those of us old guys who remember what the 70’s meant to the world of motorcycles and just what classic lines mean. Perfect.

  • Guzzto

    That is by a country mile the best thing I’ve seen in a long time. Kind of like a cb350 on stilts wearing a pretty dress and some serious hobnail workboots , it all hangs together so well, and that motor will just keep thumping along all day!

  • Perfection indeed ! Honda would sell bikes like this by the boatload today, I walk around a Honda dealers now and see nothing I want to spend my hard earned cash on ,

  • Sai666

    But the exhausts are too low though. Could this really be roughed up though?